Wearable devices and wearable assemblies with adjustable positioning for use in an optical measurement system

ABSTRACT

An optical measurement system includes a wearable device configured to be worn on a body of a user and a position alignment system. The wearable device includes a support assembly and a wearable assembly supported by the support assembly. The wearable assembly includes a plurality of light sources configured to emit a plurality of light pulses toward a target within the body of the user and a plurality of detectors each configured to receive a set of photons included in a light pulse included in the plurality of light pulses after the set of photons is scattered by the target. The position alignment system is configured to facilitate positioning of the wearable assembly at a same position on the body of the user during different use sessions of the wearable device.

RELATED APPLICATIONS

The present application is a continuation application of U.S. Pat.Application No. 17/176,466, filed Feb. 16, 2021, which claims priorityunder 35 U.S.C. §119(e) to U.S. Provisional Pat. Application No.63/086,350, filed on Oct. 1, 2020, and to U.S. Provisional Pat.Application No. 62/992,552, filed on Mar. 20, 2020, and to U.S.Provisional Pat. Application No. 62/979,866, filed on Feb. 21, 2020.These applications are incorporated herein by reference in theirrespective entireties.

BACKGROUND INFORMATION

Detecting neural activity in the brain (or any other turbid medium) isuseful for medical diagnostics, imaging, neuroengineering,brain-computer interfacing, and a variety of other diagnostic andconsumer-related applications. For example, it may be desirable todetect neural activity in the brain of a user to determine if aparticular region of the brain has been impacted by reduced bloodirrigation, a hemorrhage, or any other type of damage. As anotherexample, it may be desirable to detect neural activity in the brain of auser and computationally decode the detected neural activity intocommands that can be used to control various types of consumerelectronics (e.g., by controlling a cursor on a computer screen,changing channels on a television, turning lights on, etc.).

Neural activity and other attributes of the brain may be determined orinferred by measuring responses of tissue within the brain to lightpulses. One technique to measure such responses is time-correlatedsingle-photon counting (TCSPC). Time-correlated single-photon countingdetects single photons and measures a time of arrival of the photonswith respect to a reference signal (e.g., a light source). By repeatingthe light pulses, TCSPC may accumulate a sufficient number of photonevents to statistically determine a histogram representing thedistribution of detected photons. Based on the histogram of photondistribution, the response of tissue to light pulses may be determinedin order to study the detected neural activity and/or other attributesof the brain.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings illustrate various embodiments and are a partof the specification. The illustrated embodiments are merely examplesand do not limit the scope of the disclosure. Throughout the drawings,identical or similar reference numbers designate identical or similarelements.

FIG. 1 illustrates an exemplary optical measurement system.

FIG. 2 illustrates an exemplary detector architecture.

FIG. 3 illustrates an exemplary timing diagram for performing an opticalmeasurement operation using an optical measurement system.

FIG. 4 illustrates a graph of an exemplary temporal point spreadfunction that may be generated by an optical measurement system inresponse to a light pulse.

FIG. 5 illustrates an exemplary non-invasive wearable brain interfacesystem.

FIG. 6 shows a functional diagram of an exemplary wearable assembly thatmay implement, or be included in an implementation of, an opticalmeasurement system.

FIG. 7 illustrates an exemplary implementation in which the wearableassembly of FIG. 6 is implemented by a wearable module assembly.

FIGS. 8A to 8C illustrate an exemplary wearable device configured to beworn on a head of a user.

FIGS. 9A to 9C illustrate the exemplary wearable device of FIGS. 8A to8C with a plurality of wearable assemblies.

FIGS. 10 and 11 show side views of an exemplary wearable device as wornon a head of a user.

FIG. 12 shows a side view of another exemplary wearable device as wornon a head of a user.

FIGS. 13A and 13B illustrate exemplary configurations of an exemplaryoptical measurement system that includes a position alignment system.

FIGS. 14A and 14B illustrate exemplary implementations of a wearableheadset including a body engagement member.

FIG. 15 shows an exemplary wearable device including an integratedsensor.

FIG. 16 shows an exemplary wearable device and an external sensor.

FIGS. 17A and 17B illustrate exemplary configurations of an exemplaryoptical measurement system that includes a processing unit.

FIG. 18 illustrates an exemplary implementation of the processing unitof FIGS. 17A and 17B.

FIGS. 19-24 illustrate exemplary embodiments of a wearable device thatincludes elements of the optical measurement systems described herein.

FIG. 25 illustrates an exemplary method.

FIG. 26 illustrates an exemplary computing device.

DETAILED DESCRIPTION

Optical measurement systems, wearable devices and wearable assembliesfor use in optical measurement systems, and methods of positioningwearable devices and wearable assemblies are described herein. Forexample, an exemplary optical measurement system may include a wearabledevice including a support assembly configured to be worn on a body of auser and a wearable module assembly supported by the support assembly.The wearable module assembly includes a plurality of light sourcesconfigured to emit a plurality of light pulses toward a target withinthe body of the user and a plurality of detectors each configured toreceive a set of photons included in a light pulse included in theplurality of light pulses after the set of photons is scattered by thetarget. A position of the wearable module assembly on the supportassembly is adjustable to a conformable fitting position, as may berequired, in order to support the wearable assembly on the desiredregion-of-interest on the user’s head.. The optical measurement systemmay also include a position alignment system configured to facilitatepositioning of the wearable module assembly at a same position on thebody of the user during different use sessions of the wearable device.

The optical measurement systems and wearable assemblies described hereinprovide various benefits. For example, the wearable devices describedherein allow the position of a wearable module assembly included in awearable device to be easily adjusted to a desired position to obtainfull imaging coverage of a desired region-of-interest on the body of theuser. For example, the wearable module assembly may be adjusted to covera target area of the frontal part of the user’s head, a target area inthe rear part of the user’s head, any combination of cluster areas inthe user’s head, or coverage in the entire head. Moreover, a wearablemodule assembly may be independently moved relative to the position ofother wearable module assemblies in the wearable device to furtherenable targeted positioning of multiple regions-of-interest.Additionally, the systems, devices, assemblies, and methods describedherein enable consistent positioning of a wearable module assembly atthe same location each time the system is worn during a use session. Asa result, biological signals (e.g., neural signals) may be reliably andconsistently acquired each time the wearable device is worn during a usesession. These and other advantages and benefits of the present systemsand assemblies are described more fully herein and/or will be madeapparent in the description herein.

FIG. 1 shows an exemplary optical measurement system 100 configured toperform an optical measurement operation with respect to a body 102.Optical measurement system 100 may, in some examples, be portable and/orwearable by a user.

In some examples, optical measurement operations performed by opticalmeasurement system 100 are associated with a time domain-based opticalmeasurement technique. Example time domain-based optical measurementtechniques include, but are not limited to, TCSPC, time domain nearinfrared spectroscopy (TD-NIRS), time domain diffusive correlationspectroscopy (TD-DCS), and time domain digital optical tomography(TD-DOT).

As shown, optical measurement system 100 includes a detector 104 thatincludes a plurality of individual photodetectors (e.g., photodetector106), a processor 108 coupled to detector 104, a light source 110, acontroller 112, and optical conduits 114 and 116 (e.g., light guides, asdescribed more fully herein). However, one or more of these componentsmay not, in certain embodiments, be considered to be a part of opticalmeasurement system 100. For example, in implementations where opticalmeasurement system 100 is wearable by a user, processor 108 and/orcontroller 112 may in some embodiments be separate from opticalmeasurement system 100 and not configured to be worn by the user.

Detector 104 may include any number of photodetectors 106 as may serve aparticular implementation, such as 2^(n) photodetectors (e.g., 256, 512,..., 16384, etc.), where n is an integer greater than or equal to one(e.g., 4, 5, 8, 10, 11, 14, etc.). Photodetectors 106 may be arranged inany suitable manner.

Photodetectors 106 may each be implemented by any suitable circuitconfigured to detect individual photons of light incident uponphotodetectors 106. For example, each photodetector 106 may beimplemented by a single photon avalanche diode (SPAD) circuit and/orother circuitry as may serve a particular implementation.

Processor 108 may be implemented by one or more physical processing(e.g., computing) devices. In some examples, processor 108 may executeinstructions (e.g., software) configured to perform one or more of theoperations described herein.

Light source 110 may be implemented by any suitable component configuredto generate and emit light. For example, light source 110 may beimplemented by one or more laser diodes, distributed feedback (DFB)lasers, super luminescent diodes (SLDs), light emitting diodes (LEDs),diode-pumped solid-state (DPSS) lasers, super luminescent light emittingdiode (sLEDs), vertical-cavity surface-emitting lasers (VCSELs),titanium sapphire lasers, a micro light emitting diodes (mLEDs), and/orany other suitable laser or light source configured to emit light in oneor more discrete wavelengths or narrow wavelength bands. In someexamples, the light emitted by light source 110 is high coherence light(e.g., light that has a coherence length of at least 5 centimeters) at apredetermined center wavelength. In some examples, the light emitted bylight source 110 is emitted as a plurality of alternating light pulsesof different wavelengths.

Light source 110 is controlled by controller 112, which may beimplemented by any suitable computing device (e.g., processor 108),integrated circuit, and/or combination of hardware and/or software asmay serve a particular implementation. In some examples, controller 112is configured to control light source 110 by turning light source 110 onand off and/or setting an intensity of light generated by light source110. Controller 112 may be manually operated by a user, or may beprogrammed to control light source 110 automatically.

Light emitted by light source 110 travels via an optical conduit 114(e.g., a light pipe, a light guide, a waveguide, a single-mode opticalfiber, and/or or a multi-mode optical fiber) to body 102 of a subject.Body 102 may include any suitable turbid medium. For example, in someimplementations, body 102 is a head or any other body part of a human orother animal. Alternatively, body 102 may be a non-living object. Forillustrative purposes, it will be assumed in the examples providedherein that body 102 is a human head.

As indicated by arrow 120, light emitted by light source 110 enters body102 at a first location 122 on body 102. Accordingly, a distal end ofoptical conduit 114 may be positioned at (e.g., right above, in physicalcontact with, or physically attached to) first location 122 (e.g., to ascalp of the subject). In some examples, the light may emerge fromoptical conduit 114 and spread out to a certain spot size on body 102 tofall under a predetermined safety limit. At least a portion of lightindicated by arrow 120 may be scattered within body 102.

As used herein, “distal” means nearer, along the optical path of thelight emitted by light source 110 or the light received by detector 104,to the target (e.g., within body 102) than to light source 110 ordetector 104. Thus, the distal end of optical conduit 114 is nearer tobody 102 than to light source 110, and the distal end of optical conduit116 is nearer to body 102 than to detector 104. Additionally, as usedherein, “proximal” means nearer, along the optical path of the lightemitted by light source 110 or the light received by detector 104, tolight source 110 or detector 104 than to body 102. Thus, the proximalend of optical conduit 114 is nearer to light source 110 than to body102, and the proximal end of optical conduit 116 is nearer to detector104 than to body 102.

As shown, the distal end of optical conduit 116 (e.g., a light pipe, alight guide, a waveguide, a single-mode optical fiber, and/or amulti-mode optical fiber) is positioned at (e.g., right above, inphysical contact with, or physically attached to) output location 126 onbody 102. In this manner, optical conduit 116 may collect at least aportion of the scattered light (indicated as light 124) as it exits body102 at location 126 and carry light 124 to detector 104. Light 124 maypass through one or more lenses and/or other optical elements (notshown) that direct light 124 onto each of the photodetectors 106included in detector 104.

Photodetectors 106 may be connected in parallel in detector 104. Anoutput of each of photodetectors 106 may be accumulated to generate anaccumulated output of detector 104. Processor 108 may receive theaccumulated output and determine, based on the accumulated output, atemporal distribution of photons detected by photodetectors 106.Processor 108 may then generate, based on the temporal distribution, ahistogram representing a light pulse response of a target (e.g., tissue,blood flow, etc.) in body 102. Example embodiments of accumulatedoutputs are described herein.

FIG. 2 illustrates an exemplary detector architecture 200 that may beused in accordance with the systems and methods described herein. Asshown, architecture 200 includes a SPAD circuit 202 that implementsphotodetector 106, a control circuit 204, a time-to-digital converter(TDC) 206, and a signal processing circuit 208. Architecture 200 mayinclude additional or alternative components as may serve a particularimplementation.

In some examples, SPAD circuit 202 includes a SPAD and a fast gatingcircuit configured to operate together to detect a photon incident uponthe SPAD. As described herein, SPAD circuit 202 may generate an outputwhen SPAD circuit 202 detects a photon.

The fast gating circuit included in SPAD circuit 202 may be implementedin any suitable manner. For example, the fast gating circuit may includea capacitor that is pre-charged with a bias voltage before a command isprovided to arm the SPAD. Gating the SPAD with a capacitor instead ofwith an active voltage source, such as is done in some conventional SPADarchitectures, has a number of advantages and benefits. For example, aSPAD that is gated with a capacitor may be armed practicallyinstantaneously compared to a SPAD that is gated with an active voltagesource. This is because the capacitor is already charged with the biasvoltage when a command is provided to arm the SPAD. This is describedmore fully in U.S. Pat. Nos. 10,158,038 and 10,424,683, which areincorporated herein by reference in their entireties.

In some alternative configurations, SPAD circuit 202 does not include afast gating circuit. In these configurations, the SPAD included in SPADcircuit 202 may be gated in any suitable manner.

Control circuit 204 may be implemented by an application specificintegrated circuit (ASIC) or any other suitable circuit configured tocontrol an operation of various components within SPAD circuit 202. Forexample, control circuit 204 may output control logic that puts the SPADincluded in SPAD circuit 202 in either an armed or a disarmed state.

In some examples, control circuit 204 may control a gate delay, whichspecifies a predetermined amount of time control circuit 204 is to waitafter an occurrence of a light pulse (e.g., a laser pulse) to put theSPAD in the armed state. To this end, control circuit 204 may receivelight pulse timing information, which indicates a time at which a lightpulse occurs (e.g., a time at which the light pulse is applied to body102). Control circuit 204 may also control a programmable gate width,which specifies how long the SPAD is kept in the armed state beforebeing disarmed.

Control circuit 204 is further configured to control signal processingcircuit 208. For example, control circuit 204 may provide histogramparameters (e.g., time bins, number of light pulses, type of histogram,etc.) to signal processing circuit 208. Signal processing circuit 208may generate histogram data in accordance with the histogram parameters.In some examples, control circuit 204 is at least partially implementedby controller 112.

TDC 206 is configured to measure a time difference between an occurrenceof an output pulse generated by SPAD circuit 202 and an occurrence of alight pulse. To this end, TDC 206 may also receive the same light pulsetiming information that control circuit 204 receives. TDC 206 may beimplemented by any suitable circuitry as may serve a particularimplementation.

Signal processing circuit 208 is configured to perform one or moresignal processing operations on data output by TDC 206. For example,signal processing circuit 208 may generate histogram data based on thedata output by TDC 206 and in accordance with histogram parametersprovided by control circuit 204. To illustrate, signal processingcircuit 208 may generate, store, transmit, compress, analyze, decode,and/or otherwise process histograms based on the data output by TDC 206.In some examples, signal processing circuit 208 may provide processeddata to control circuit 204, which may use the processed data in anysuitable manner. In some examples, signal processing circuit 208 is atleast partially implemented by processor 108.

In some examples, each photodetector 106 (e.g., SPAD circuit 202) mayhave a dedicated TDC 206 associated therewith. For example, for an arrayof N photodetectors 106, there may be a corresponding array of N TDCs206. Alternatively, a single TDC 206 may be associated with multiplephotodetectors 106. Likewise, a single control circuit 204 and a singlesignal processing circuit 208 may be provided for one or more SPADcircuits 202 and/or TDCs 206.

FIG. 3 illustrates an exemplary timing diagram 300 for performing anoptical measurement operation using optical measurement system 100. Theoptical measurement operation may be performed in accordance with a timedomain-based technique, such as TD-NIRS. Optical measurement system 100may be configured to perform the optical measurement operation bydirecting light pulses (e.g., laser pulses) toward a target within abody (e.g., body 102). The light pulses may be short (e.g., 10-2000picoseconds (ps)) and repeated at a high frequency (e.g., between100,000 hertz (Hz) and 100 megahertz (MHz)). The light pulses may bescattered by the target and at least a portion of the scattered lightmay be detected by optical measurement system 100. Optical measurementsystem 100 may measure a time relative to the light pulse for eachdetected photon. By counting the number of photons detected at each timerelative to each light pulse repeated over a plurality of light pulses,optical measurement system 100 may generate a histogram that representsa light pulse response of the target (e.g., a temporal point spreadfunction (TPSF)). The terms histogram and TPSF are used interchangeablyherein to refer to a light pulse response of a target.

Timing diagram 300 shows a sequence of light pulses 302 (e.g., lightpulses 302-1 and 302-2) that may be applied to the target (e.g., tissuewithin a brain of a user, blood flow, a fluorescent material used as aprobe in a body of a user, etc.). Timing diagram 300 also shows a pulsewave 304 representing predetermined gated time windows (also referred asgated time periods) during which photodetectors 106 are gated ON todetect photons. As shown, light pulse 302-1 is applied at a time t₀. Ata time t₁, a first instance of the predetermined gated time windowbegins. Photodetectors 106 may be armed at time t₁, enablingphotodetectors 106 to detect photons scattered by the target during thepredetermined gated time window. In this example, time t₁ is set to beat a certain time after time t₀, which may minimize photons detecteddirectly from the laser pulse, before the laser pulse reaches thetarget. However, in some alternative examples, time t₁ is set to beequal to time t₀.

At a time t₂, the predetermined gated time window ends. In someexamples, photodetectors 106 may be disarmed at time t₂. In otherexamples, photodetectors 106 may be reset (e.g., disarmed and re-armed)at time t₂ or at a time subsequent to time t₂. During the predeterminedgated time window, photodetectors 106 may detect photons scattered bythe target. Photodetectors 106 may be configured to remain armed duringthe predetermined gated time window such that photodetectors 106maintain an output upon detecting a photon during the predeterminedgated time window. For example, a photodetector 106 may detect a photonat a time t₃, which is during the predetermined gated time windowbetween times t₁ and t₂. The photodetector 106 may be configured toprovide an output indicating that the photodetector 106 has detected aphoton. The photodetector 106 may be configured to continue providingthe output until time t₂, when the photodetector may be disarmed and/orreset. Optical measurement system 100 may generate an accumulated outputfrom the plurality of photodetectors. Optical measurement system 100 maysample the accumulated output to determine times at which photons aredetected by photodetectors 106 to generate a TPSF.

FIG. 4 illustrates a graph 400 of an exemplary TPSF 402 that may begenerated by optical measurement system 100 in response to a light pulse404 (which, in practice, represents a plurality of light pulses). Graph400 shows a normalized count of photons on a y-axis and time bins on anx-axis. As shown, TPSF 402 is delayed with respect to a temporaloccurrence of light pulse 404. In some examples, the number of photonsdetected in each time bin subsequent to each occurrence of light pulse404 may be aggregated (e.g., integrated) to generate TPSF 402. TPSF 402may be analyzed and/or processed in any suitable manner to determine orinfer biological (e.g., neural) activity.

Optical measurement system 100 may be implemented by or included in anysuitable device(s). For example, optical measurement system 100 may beincluded in a non-wearable device (e.g., a medical device and/orconsumer device that is placed near the head or other body part of auser to perform one or more diagnostic, imaging, and/or consumer-relatedoperations). Optical measurement system 100 may alternatively beincluded, in whole or in part, in a sub-assembly enclosure of a wearableinvasive device (e.g., an implantable medical device for brain recordingand imaging).

Alternatively, optical measurement system 100 may be included, in wholeor in part, in a non-invasive wearable device that a user may wear toperform one or more diagnostic, imaging, analytical, and/orconsumer-related operations. The non-invasive wearable device may beplaced on a user’s head or other part of the user to detect neuralactivity. In some examples, such neural activity may be used to makebehavioral and mental state analysis, awareness and predictions for theuser.

Mental state described herein refers to the measured neural activityrelated to physiological brain states and/or mental brain states, e.g.,joy, excitement, relaxation, surprise, fear, stress, anxiety, sadness,anger, disgust, contempt, contentment, calmness, focus, attention,approval, creativity, positive or negative reflections/attitude onexperiences or the use of objects, etc. Further details on the methodsand systems related to a predicted brain state, behavior, preferences,or attitude of the user, and the creation, training, and use of neuromescan be found in U.S. Provisional Pat. Application No. 63/047,991, filedJul. 3, 2020. Exemplary measurement systems and methods usingbiofeedback for awareness and modulation of mental state are describedin more detail in U.S. Pat. Application No. 16/364,338, filed Mar. 26,2019, published as US2020/0196932A1. Exemplary measurement systems andmethods used for detecting and modulating the mental state of a userusing entertainment selections, e.g., music, film/video, are describedin more detail in U.S. Pat. Application No. 16/835,972, filed Mar. 31,2020, published as US2020/031 551 0A1. Exemplary measurement systems andmethods used for detecting and modulating the mental state of a userusing product formulation from, e.g., beverages, food, selectivefood/drink ingredients, fragrances, and assessment based onproduct-elicited brain state measurements are described in more detailin U.S. Pat. Application No. 16/853,614, filed Apr. 20, 2020, publishedas US2020/0337624A1. Exemplary measurement systems and methods used fordetecting and modulating the mental state of a user through awareness ofpriming effects are described in more detail in U.S. Pat. ApplicationNo. 16/885,596, filed May 28, 2020, published as US2020/0390358A1. Theseapplications and corresponding U.S. publications are incorporated hereinby reference in their entirety.

FIG. 5 shows an exemplary non-invasive wearable brain interface system500 (“brain interface system 500”) that implements optical measurementsystem 100 (shown in FIG. 1 ). As shown, brain interface system 500includes a head-mountable component 502 configured to be attached toand/or worn on a user’s head. Head-mountable component 502 may beimplemented by a cap shape that is worn on a head of a user. Alternativeimplementations of head-mountable component 502 include helmets,beanies, headbands, other hat shapes, or other forms conformable to beworn on a user’s head, etc. Head-mountable component 502 may be made outof any suitable cloth, soft polymer, plastic, hard shell, and/or anyother suitable material as may serve a particular implementation.Examples of headgears used with wearable brain interface systems aredescribed below in more detail and in U.S. Pat. No. 10,340,408,incorporated herein by reference in its entirety.

Head-mountable component 502 includes a plurality of detectors 504,which may implement or be similar to detector 104, and a plurality oflight sources 506, which may be implemented by or be similar to lightsource 110. It will be recognized that in some alternative embodiments,head-mountable component 502 may include a single detector 504 and/or asingle light source 506.

Brain interface system 500 may be used for controlling an optical pathto the brain and/or for transforming photodetector measurements into anintensity value that represents an optical property of a target withinthe brain. Brain interface system 500 allows optical detection of deepanatomical locations beyond skin and bone (e.g., skull) by extractingdata from photons originating from light sources 506 and emitted to atarget location within the user’s brain, in contrast to conventionalimaging systems and methods (e.g., optical coherence tomography (OCT),continuous wave near infrared spectroscopy (CW-NIRS)), which only imagesuperficial tissue structures or through optically transparentstructures.

Brain interface system 500 may further include a processor 508configured to communicate with (e.g., control and/or receive signalsfrom) detectors 504 and light sources 506 by way of a communication link510. Communication link 510 may include any suitable wired and/orwireless communication link. Processor 508 may include any suitablehousing and may be located on the user’s scalp, neck, shoulders, chest,or arm , as may be desirable. In some variations, processor 508 may beintegrated in the same assembly housing as detectors 504 and lightsources 506. In some examples, processor 508 is implemented by orsimilar to processor 108 and/or controller 112.

As shown, brain interface system 500 may optionally include a remoteprocessor 512 in communication with processor 508. For example, remoteprocessor 512 may store measured data from detectors 504 and/orprocessor 508 from previous detection sessions and/or from multiplebrain interface systems (not shown). In some examples, remote processor512 is implemented by or similar to processor 108 and/or controller 112.

Power for detectors 504, light sources 506, and/or processor 508 may beprovided via a wearable battery (not shown). In some examples, processor508 and the battery may be enclosed in a single housing, and wirescarrying power signals from processor 508 and the battery may extend todetectors 504 and light sources 506. Alternatively, power may beprovided wirelessly (e.g., by induction).

In some alternative embodiments, head mountable component 502 does notinclude individual light sources. Instead, a light source configured togenerate the light that is detected by detector 504 may be includedelsewhere in brain interface system 500. For example, a light source maybe included in processor 508 and/or in another wearable or non-wearabledevice and coupled to head mountable component 502 through an opticalconnection.

In some alternative embodiments, head mountable component 502 does notinclude individual detectors 504. Instead, one or more detectorsconfigured to detect the scattered light from the target may be includedelsewhere in brain interface system 500. For example, a detector may beincluded in processor 508 and/or in another wearable or non-wearabledevice and coupled to head mountable component 502 through an opticalconnection.

FIG. 6 shows a functional diagram of an exemplary wearable assembly 600that may implement, or be included in an implementation of, opticalmeasurement system 100. Wearable assembly 600 includes N light sources602 (e.g., light sources 602-1 through 602-N) and M detectors 604 (e.g.,detectors 604-1 through 604-M). Wearable assembly 600 may include any ofthe other components of optical measurement system 100 as may serve aparticular implementation. N and M may each be any suitable value (i.e.,there may be any number of light sources 602 and any number of detectors604 included in wearable assembly 600 as may serve a particularimplementation).

Light sources 602 are each configured to emit light (e.g., a sequence oflight pulses) and may be implemented by any of the light sourcesdescribed herein. Detectors 604 may each be configured to detect arrivaltimes for photons of the light emitted by one or more light sources 602after the light is scattered by the target. For example, a detector 604may include a photodetector configured to generate a photodetectoroutput pulse in response to detecting a photon of the light and a TDCconfigured to record a timestamp symbol in response to an occurrence ofthe photodetector output pulse, the timestamp symbol representative ofan arrival time for the photon (i.e., when the photon is detected by thephotodetector). Detectors 604 may be implemented by any of the detectorsdescribed herein.

Wearable assembly 600 may be implemented by or included in any of thewearable devices, wearable module assemblies, and/or wearable unitsdescribed herein. For example, wearable assembly 600 may be implementedby or included in a wearable device (e.g., headgear) configured to beworn on a user’s head. Wearable assembly 600 may additionally oralternatively be implemented by a wearable device configured to be wornon any other part of a user’s body.

Wearable assembly 600 may be modular in that one or more components ofwearable assembly 600 may be removed, changed out, or otherwise modifiedas may serve a particular implementation. Additionally or alternatively,wearable assembly 600 may be modular such that one or more components ofwearable assembly 600 may be housed in a separate housing (e.g., module)and/or may be movable relative to other components. Exemplary modularwearable assemblies are described in more detail in U.S. ProvisionalPat. Application No. 63/081,754, filed Sep. 22, 2020, U.S. ProvisionalPat. Application No. 63/038,459, filed Jun. 12, 2020, U.S. ProvisionalPat. Application No. 63/038,468, filed Jun. 12, 2020, U.S. ProvisionalPat. Application No. 63/038,481, filed Jun. 12, 2020, and U.S.Provisional Pat. Application No. 63/064,688, filed Aug. 12, 2020, whichapplications are incorporated herein by reference in their respectiveentireties.

FIG. 7 illustrates an exemplary implementation of a modular wearableassembly. FIG. 7 is illustrative of one of many differentimplementations of wearable assembly 600 that may be realized inaccordance with the principles described herein. As shown in FIG. 7 ,wearable assembly 600 is implemented by a wearable module assembly 700.Wearable module assembly 700 includes a plurality of wearable modules702 (e.g., modules 702-1 through 702-3). However, wearable moduleassembly 700 may alternatively include a single wearable module 702.Module 702-1 can represent or include a first module housing, module702-2 can represent or include a separate second module housing, module703-3 can represent or include a separate third module housing, and soforth. While three modules 702 are shown to be included in wearablemodule assembly 700, in alternative configurations, any number ofmodules 702 (e.g., a single module up to sixteen or more modules) may beincluded in wearable module assembly 700.

Each module 702 includes a light source 704 (e.g., light source 704-1 ofmodule 702-1, light source 704-2 of module 702-2, and light source 704-3of module 702-3) and a plurality of detectors 706 (e.g., detectors706-11 through 706-16 of module 702-1, detectors 706-21 through 706-26of module 702-2, and detectors 706-31 through 706-36 of module 702-3).Each module 702 may include any other components as may serve aparticular implementation.

In the particular implementation shown in FIG. 7 , each module 702includes a single light source 704 (labeled “S”) and six detectors 706(each labeled “D”). However, each module 702 may have any other numberand arrangement of light sources 704 and detectors 706 as may serve aparticular implementation. Any one or more components of a module 702(e.g., a light source 704, detectors 706, and/or any other components)may be housed, in whole or in part, within a module housing.

Each light source 704 may be implemented by any light source describedherein and may be configured to emit a light pulse directed at a target(e.g., the brain). For example, light source 704-1 may emit a firstlight pulse toward the target and light source 704-2 may emit a secondlight pulse toward the target. In some examples, each light source 704housed within module 702 includes one or more light-generatingcomponents (e.g., laser diodes). Each light source 704 may additionallyinclude any suitable optical components (e.g., an optical conduit)configured to guide and direct emitted light toward the target. In someexamples, a portion of each light source 704 (e.g., an optical conduit)protrudes from a front surface 708 of the module 702 (e.g., a surface ofmodule 702 facing, or parallel to a surface of, the body of the userwhen wearable module assembly 700 is worn by the user) to facilitatecontact of light source 704 with the body of the user and/or topenetrate through the user’s hair.

Each light source 704 may be located at a center region of front surface708. In alternative implementations, a light source 704 of a module 702may be located at any other location on the module. In alternativeconfigurations (not shown) of a module 702, one or more components ofthe light source 704 (e.g., laser diodes) may be located remotely in/onanother device separate from module 702, and the generated light may beconveyed to module 702 by another optical conduit (e.g., optical fibers,etc.).

Each detector 706 may be implemented by any detector described hereinand may include a plurality of photodetectors (e.g., SPADs) as well asother circuitry (e.g., TDCs, RF antennas, inductive coupling coils)housed within module 702. Each detector 706 may be configured to detectarrival times for photons of the light emitted by one or more lightsources after the photons are scattered by the target. For example,detector 706-11 may detect a first set of photons included in the firstlight pulse after the first set of photons are scattered by the target,and detector 706-21 may detect a second set of photons included in thesecond light pulse after the second set of photons are scattered by thetarget. In some examples, each detector 706 housed within module 702 mayalso include any suitable optical components (e.g., an optical conduit)configured to receive and guide photons scattered by the target towardthe plurality of photodetectors included in the detector 706. In someexamples, a portion of each detector 706 (e.g., an optical conduit)protrudes from front surface 708 to facilitate contact with the body ofthe user and/or to penetrate through the user’s hair.

In alternative configurations (not shown) of a module 702, one or morecomponents of a detector 706 (e.g., a photodetector) may be locatedremotely in/on another device separate from the module 702, and thescattered photons received by detector 706 are conveyed from the module702 by another optical conduit (e.g., optical fibers, etc.) to theremote component.

Wearable module assembly 700 also includes a connecting assembly 710that physically connects individual modules 702 with one another. Insome examples, connecting assembly 710 flexibly connects modules 702such that wearable module assembly 700 is conformable to a 3D(non-planar) surface, such as a surface of the user’s body (e.g., theuser’s head), when the wearable module assembly 700 is worn by the user.

Connecting assembly 710 may be implemented by any suitable device,structure, connectors, or mechanism as may suit a particularimplementation. For example, as shown in FIG. 7 , connecting assembly710 is implemented by a plurality of connectors 712 (e.g., connectors712-1 to 712-3) between adjacent modules 702. In additional oralternative configurations, connecting assembly 710 may be implementedby a common support assembly that indirectly connects modules 702. Thecommon support assembly may include, for example, an open-mesh (e.g.,web-like) structure, a closed-surface structure (e.g., a flex circuit),and/or any other suitable assembly.

In the examples described above, wearable modules 702 included inwearable module assembly 700 operate in accordance with a time-domainoptical measurement modality (e.g., TD-NIRS). In other examples,wearable module assembly 700 may include one or more auxiliary modulesthat operate in accordance with a different measurement modality, suchas continuous wave NIRS (CW-NIRS), frequency-domain NIRS (FD-NIRS),electroencephalography (EEG), electromyography (EMG),magnetoencephalography (MEG), positron emission tomography (PET),functional magnetic resonance imaging (fMRI), single-photon emissioncomputed tomography (SPECT), functional ultrasound imaging (fUS), andany other imaging modality as may serve a particular implementation.

As mentioned above, wearable assembly 600 (e.g., wearable moduleassembly 700) may be included in or implemented by a wearable devicethat may be worn on a body of a user. Exemplary wearable devices willnow be described. In the examples that follow the wearable devices aredescribed as headgear configured to be worn on a user’s head. However,the wearable devices may have any other suitable form and may beconfigured to be worn on any other part of a user’s body as may serve aparticular implementation.

FIGS. 8A to 9C illustrate an exemplary wearable device 800 configured tobe worn on a head of a user. FIG. 8A shows a side view of wearabledevice 800, FIG. 8B shows a top view of wearable device 800, and FIG. 8Cshows a front view of wearable device 800. As shown in FIGS. 8A to 8C,wearable device 800 includes a support assembly 802 configured tosupport a wearable assembly (not shown), such as wearable assembly 600or wearable module assembly 700. FIGS. 9A to 9C show wearable device 800with a plurality of wearable assemblies 902 (e.g., wearable assemblies902-1 to 902-3) supported on support assembly 802. While FIGS. 9A to 9Cshow three wearable assemblies 902, wearable device 800 may include anyother number of wearable assemblies 902 as may serve a particularimplementation. Wearable device 800 may also include any othercomponents as may serve a particular implementation.

Support assembly 802 is configured to be worn on the body of the userand support (e.g., hold) each wearable assembly 902 (see FIGS. 9A-9C)over a region-of-interest on the user’s body. Support assembly 802includes a body support portion 804 and a plurality of support members806 (e.g., support member 806-1 to 806-3). Body support portion 804 isconfigured to rest on, or be supported by, the user’s body. For example,as shown in FIGS. 8A-9C, body support portion 804 is in the form of aheadband configured to be worn around a user’s head. However, bodysupport portion 804 may have any other suitable shape or configurationthat allows body support portion 804 to be worn on and/or conform to theuser’s head or body (e.g., earpieces, nosepiece, etc.). Body supportportion 804 may be formed of any suitable material and may be flexibleor rigid as may serve a particular implementation. In some examples,body support portion 804 is adjustable to achieve a desired fit on theuser’s head.

As shown in FIGS. 9A-9C, each support member 806 is configured tosupport (e.g., hold, maintain, etc.) one or more wearable assemblies 902over a target (e.g., the brain) within the user’s body. Each supportmember 806 is connected at both ends to body support portion 804 andcrosses over a portion of the user’s head when support assembly 802 isworn on the head. While FIGS. 8A-9C show that support assembly 802includes three support members 806, support assembly 802 may have anyother suitable number of support members 806 (e.g., one, two, or morethan three). Moreover, while FIGS. 8A-9C show that support members 806extend from the front of body support portion 804 (e.g., a portion thatis worn near the user’s forehead) to the back of body support portion804 (e.g., a portion that is worn near the back of the user’s head),support members 806 may be connected to body support portion 804 at anyother suitable locations. In some examples, support members 806 extendfrom a left side to a right side of body support portion 804. In yetfurther examples, support assembly 802 includes crossing orinterconnected support members, such as a set of support members 806that extend from front to back and another set of support members 806that extend from left to right to form a web-like structure.

Support members 806 may be formed of any suitable material and may beflexible, elastic, or rigid. For example, support members 806 may beimplemented by elastic cords, flexible nylon straps, rigid rails, or acombination of these. Support members 806 may be connected to bodysupport portion 804 by any suitable connection mechanisms, such as butnot limited to buttons, hook-and-loop fasteners, buckles, snaps, rings,grommets or slits in body support portion 804, clamps, worm gears,ratchets, clips, ties, elastic bands, screws or fasteners, cord locks,toggles, spring locks, stoppers, and the like. In some examples, supportmembers 806 are permanently connected to body support portion 804. Forinstance, support members 806 may be integrally formed with body supportportion 804.

In additional or alternative examples, support members 806 areadjustably connected to body support portion 804. For example, one ormore of a position, length, or tension of a support member 806 may beadjustable. To illustrate, the position of a support member 806 relativeto body support portion 804 may be adjustable by changing the locationon body support portion 804 where support member 806 is connected tobody support portion 804. For example, body support portion 804 mayinclude a plurality of connection locations (e.g., buttons, snaps,hooks, etc.) at which support member 806 may be connected. The positionof support member 806 may additionally or alternatively be adjusted bypivoting support member 806 about its connection point with body supportportion 804. As another example, the position of support member 806 maybe adjusted by adjusting one or more bands or other support members 806that are connected to the support member (e.g., at a location betweenconnection points with body support portion 804). The length of supportmember 806 may be adjusted by changing the length of support member 806between connection points on body support portion 804. For instance,support member 806 may be a flexible strap and the length of the strapbetween connection points on body support portion 804 may be adjusted bymeans of an adjustable buckle or cord lock. As another illustration, thelength of support member 806 may be adjusted by pushing or pulling aback portion of support member 806 through a locking mechanism (e.g., aratchet or worm gear). The tension of an elastic support member 806 mayalso be adjusted to shorten or elongate the support member 806.

Each wearable assembly 902 may be supported by support members 806 inany suitable way. In some examples, a wearable assembly 902 ispermanently or non-movably held or supported by one or more supportmembers 806. Alternatively, the wearable assembly 902 may be adjustablyconnected to one or more support members 806 such that the wearableassembly 902 may change position along support member 806 or may rotateabout a connection point with support member 806. For instance, wearableassembly 902-1 may include one or more connectors that movably engagewith support member 806-1 to adjustably hold wearable assembly 902-1 onsupport member 806-1. The connectors may be implemented by any suitabledevices or mechanisms, such as hoops, hooks, rings, grooves, cord locks,and/or any other device or mechanism. Alternatively, wearable assembly902 may be connected to support members 806 by adjustable fasteners(e.g., screws, hook-and-loop fasteners, etc.). In some examples, theposition of wearable assembly 902 on support member 806 may be locked bya locking mechanism (e.g., a cord lock, a tension lock, a friction lock,etc.). In yet further examples, wearable assembly 902 may be movablyconnected to a support member 806 by way of a carriage (not shown) thatis movably connected to support member 806 and that is configured tohold wearable assembly 902.

Each wearable assembly 902 may be connected to a support member 806 byway of a wearable module (e.g., a module 702) included in the wearableassembly and/or by way of a connecting assembly (e.g., connectingassembly 710) that connects or supports a plurality of wearable modulestogether in a wearable module assembly (e.g., wearable module assembly700).

As mentioned, in some examples support members 806 may be implemented byrails. A rail, body support portion 804 to which the rail is connected,and/or a wearable assembly 902 supported by the rail may use a ratchetand pawl type mechanism, a lead-screw, pulleys and gears/wheels, treadsand sprockets, friction locks, screw locks, or any other mechanisms ordevices, or combination thereof, for adjusting the rail and/or wearableassembly 902 supported by the rail. In some examples, the rails mayinclude marks or other means of positional indication including rotaryencoders, linear encoders, strain gauges, RF antennas, magnets, orcombination thereof, for indicating the various positions along therails. In this way, the length of a rail and the position of wearableassembly 902 on the rail can be identified and repeated, as necessary.The rails may also indicate marks, rotary encoders, or any other meansof angular indication to indicate the angle of the rails relative tobody support portion 804 or some other reference member.

Adjustment of support member 806 and/or wearable assemblies 902 can bemade manually, automatically, and/or with assistance from motorizedmechanisms. For example, a motorized mechanize may be configured to pullsupport members 806 to preset locations. The preset locations may bebased on a known mechanical encoding or similar ratcheting feature forknowing how much of the support member 806 has been pulled.Alternatively, a support member 806 could be pulled until a certainlevel of tension is reached, as determined by an attached sensor.Control circuitry may be used to provide control of the mechanicalsupport members 806 such that the coupling is optimized as determined byonline analysis of signal-to-noise ratio or other metric. In someexamples, different users could share a device with each user having adifferent preset configuration that is stored in non-volatile memory onthe device.

In some examples, support members 806 are configured to conform to theuser’s body (e.g., head). For instance, flexible and/or elastic bandsmay be configured to be stretched or pulled tight to bring wearableassembly 902 (e.g., light emitters and light receivers) into contactwith the user’s head. Rigid rails may be shaped (e.g., curved) toconform to the shape of the user’s head. As a result, support assembly802 is configured to pull each wearable assembly 902 tight against theuser’s head, thereby ensuring better coupling to the tissue for signalacquisition from the target. Some wearable devices may include acombination of the conformal and rigid type systems. For example, arigid body support portion 804 may be combined with flexible or elasticsupport members 806, and vice versa.

In some examples, support members 806 may support wearable units,devices, or modules of measurement modalities different from time-domainoptical modalities (e.g., EEG, EKG, EMG, MEG, EOG, eye/pupil tracking,etc.) for detecting or recording brain signals or other biologicalsignals from the user.

Support assembly 802 also allows wearable assemblies 902 (e.g., wearablemodules 702 in wearable module assemblies 700) to be packed in anydesired configuration by the positioning of support members 806 and/orwearable assemblies 902 on support members 806. For example, supportmembers 806 may be sparsely populated across the rigid structure, or maybe positioned in close proximity to one another to allow for denselypacking modules together in clusters for higher signal fidelityacquisition. Support members 806 may be added or removed as needed basedon the desired use case, or may be permanently incorporated into supportassembly 802.

With the configurations of support assembly 802 describe herein, aposition of wearable assembly 902 on support assembly 802 may beadjustable. That is, a location of wearable assembly 902 in athree-dimensional space relative to body support portion 804 or asupport member 806 that supports wearable assembly 902 is adjustable.Thus, when wearable device 800 is worn by a user, the position ofwearable assembly 902 may be adjusted to cover a desiredregion-of-interest. In some examples, the region-of-interest is aparticular functional region of the brain, such as the cerebrum, thecerebellum, the cerebral cortex, a particular lobe (e.g., frontal lobe,parietal lobe, occipital lobe, temporal lobe, anterior lobe, posteriorlobe, flocculonodular lobe, etc.) or a particular area within a lobe orother brain region (e.g., Wernicke’s Area, Broca’s Area, prefrontalcortex, the visual area, the motor function area, etc.). The position ofwearable assembly 902 may be adjusted so that the entire functionalregion of the brain is imaged by the optical measurement system. Inexamples in which wearable device 800 includes multiple differentwearable assemblies 902, wearable assemblies 902 may also be movablerelative to one another. In this way, each wearable assembly 902 can bepositioned to target a different region-of-interest and/or toaccommodate different user head morphologies.

The adjustability of wearable assemblies 902 will be illustrated withreference to FIGS. 10 and 11 . FIG. 10 shows a side view of an exemplarywearable device 1000 as worn on a head 1002 of a user. Wearable device1000 includes a support assembly 1004 supporting a plurality of distinctwearable module assemblies 1006 (e.g., wearable module assemblies 1006-1through 1006-4). Each wearable module assembly 1006 may be implemented,for example, by wearable module assembly 700 and includes a plurality ofwearable modules 1008 (e.g., wearable modules 702). For example, FIG. 10shows five wearable modules 1008 grouped together to form wearablemodule assembly 1006-1 and the five wearable modules 1008 are positionedon a desired region-of-interest on the user’s head 1002.

Support assembly 1004 includes a body support portion 1010 and aplurality of support members 1012 (e.g., support members 1012-1 through1012-3). Support member 1012-1 supports wearable module assembly 1006-1,support member 1012-2 supports wearable module assembly 1006-2, andsupport member 1012-3 supports wearable module assemblies 1006-3 and1006-4. As shown in FIG. 10 , support members 1012 are positionedbeneath wearable module assemblies 1006 (i.e., positioned betweenwearable module assemblies 1006 and head 1002 of a user. In alternativeconfigurations, support members 1012 may be positioned on top ofwearable module assemblies 1006.

FIG. 11 shows a side view of wearable device 1000 after wearable moduleassemblies 1006 have been adjusted. As shown in FIG. 11 , a position ofeach wearable module assembly 1006 has been adjusted on support assembly1004 and relative to each of the other wearable module assemblies 1006and relative to the desired region-of-interest on the user’s head 1002.Accordingly, wearable module assemblies 1006 have been re-positioned toachieve more spatially uniform and expansive coverage of a desiredregion-of-interest .

In some examples, a wearable device may include a pressing memberconfigured to press the wearable assemblies supported by the supportassembly into contact with the user’s body when the wearable device isworn on the body of the user. The pressing member may include, forexample, an elastic band, a strap, a hat or cap, an inflatable bagwithin a helmet, a liquid filled flexible shell/bag, springs, permanentmagnets, electromagnets, or any other suitable device configured topress, to a conformable fitting position as may serve a particular usesession, the wearable assembly against the body surface. For instance,the helmets shown in FIGS. 19 and 20 may cover and press a wearableassembly 600 against the user’s head to a conformable fitting position,as may be required, in order to support the wearable assembly on thedesired region-of-interest on the user’s head. In some examples, the fitof the helmets is adjustable to produce the pressing force. Thus, thepressing member may help maintain light sources 602 and detectors 604 incontact with the body surface.

In the embodiments described above, support assembly 802 includes a bodysupport portion 804 and one or more support members 806 connected tobody support portion 804. In alternative embodiments, support assembly802 comprises a plurality of support members 806 that directlyinterconnect different wearable assemblies 902, as illustrated in FIG.12 . FIG. 12 is similar to FIG. 10 except that in FIG. 12 supportassembly 1004 comprises a plurality of assembly connectors 1202 (e.g.,assembly connectors 1202-1 to 1202-5) that interconnect wearable moduleassemblies 1006. For example, assembly connector 1202-1 connectswearable module assembly 1006-1 to wearable module assembly 1006-2,assembly connector 1202-2 connects wearable module assembly 1006-2 towearable module assembly 1006-3, and so on.

Assembly connectors 1202 may be implemented by any suitable connectingmechanism, including any connecting mechanism described herein. Assemblyconnectors 1202 may connect adjacent wearable module assemblies 1006 byway of any wearable module 1008 and/or connecting assembly (not shown)included in the wearable module assemblies 1006. Assembly connectors1202 may be adjustable to thereby facilitate adjustment of positions ofwearable module assemblies 1006 relative to one another and relative tothe target. For example, assembly connectors 1202 may be implemented byadjustable straps and side-release buckles. Accordingly, a length ofassembly connectors 1202 may be lengthened or shortened as desired toadjust positions of wearable module assemblies 1006.

As shown in FIG. 12 , support assembly 1004 does not include bodysupport portion 804. However, in some embodiments (not shown) supportassembly 1004 may include body support portion 1010 and wearable moduleassemblies 1006 may also be connected to body support portion 1010 byway of one or more additional connectors.

In some scenarios, it may be important to position the wearable deviceand/or the wearable assemblies included in the wearable device at thesame position on the user’s body and/or relative to the desiredregion-of-interest during multiple different use sessions. Consistentplacement enables the repeatable acquisition of consistent data acrossdifferent use sessions that can be easily compared and analyzed. In someexamples, optical measurement systems described herein (e.g., opticalmeasurement system 100) may include a position alignment systemconfigured to facilitate consistent positioning of a wearable device,wearable assembly, wearable module assembly, and/or wearable module onthe user’s body during different use sessions. For example, FIGS.13A-13B show illustrative configurations 1300-1 and 1300-2 of anexemplary optical measurement system 1302 in accordance with theprinciples described herein.

Optical measurement system 1302 may be an implementation of opticalmeasurement system 100 and, as shown, includes a wearable device 1304and a position alignment system 1306. Wearable device 1304 may beimplemented by any wearable device described herein (e.g., wearabledevice 800 or 1000) and may include any one or more wearable assemblies1308 (e.g., wearable assemblies 1308-1 to 1308-N) described herein.Position alignment system 1306 may implement any mechanical-based,sensor-based, and/or signal-based devices and/or operations to obtainconsistent positioning of wearable device 1304 and/or wearableassemblies 1308. Optical measurement system 1302 may also include anyother components as may serve a particular implementation.

In configuration 1300-1, position alignment system 1306 is integrated inwearable device 1304 (e.g., in a housing of a module 702, in or onsupport assembly 802, etc.), as will be described below in more detail.In configuration 1300-2, position alignment system 1306 is notintegrated in wearable device 1304. For example, position alignmentsystem 1306 may be included in a wearable device separate from wearabledevice 1304 (e.g., a mobile device). In some configurations (not shown),position alignment system 1306 is distributed across components includedin both wearable device 1304 and components located remotely fromwearable device 1304. In alternative configurations (not shown),position alignment system 1306 is not included in optical measurementsystem 1302 but is a standalone system that is physically andelectrically unconnected with optical measurement system 1302.

As mentioned, position alignment system 1306 may implement mechanicaldevices and alignment methods. In such examples, wearable device 1304may include one or more body engagement members configured to engagewith (e.g., rest on, touch, fit into, etc.) anatomical features of theuser’s body to facilitate consistent placement of the wearable device onthe user’s body. The body engagement members may be connected to asupport assembly of wearable device 1304 (e.g., support assembly 802).To illustrate, as shown in FIG. 14A, a wearable headset 1400A includes asupport assembly 1402 and right and left earpieces 1404R and 1404Lconnected to support assembly 1402 and configured to rest in the user’sears (e.g., in the outer ear canal). As another example (not shown),earpieces 1404 may include ear cups that rest on or envelope the ears.In another example shown in FIG. 14B, a wearable headset 1400B includesa nosepiece 1406 connected to support assembly 1402 and configured torest on the bridge of the user’s nose.

It will be recognized that earpieces 1404 and nosepiece 1406 are merelyillustrative, as the body engagement members may take any other suitableform and may engage with any other feature of the user’s body. Forexample, a body engagement member may include a structure (e.g., a ring,a band, a pad, etc.) configured to rest on the user’s inion at the backof the user’s head. As another example, the body engagement member mayinclude a chinstraps configured to engage with the user’s body under thechin. In some examples, wearable device 1304 may have three or morepoints of contact with anatomical features (e.g., both ears and the nosebridge), thereby improving accuracy in consistent placement. Expandedfoam or molded padding may also be used and configured to engage withthe user’s body where needed for repeatable positioning and positionmaintenance.

In some examples, the body engagement members are adjustable so thatthey may be customized for a particular user. The position of the bodyengagement members may be indicated by markings on the body engagementmembers or support assembly. The body engagement members may be lockedwhen the appropriate fit is set to prevent misalignment during use andso that the same fit may be achieved during each subsequent use session.Additionally or alternatively, the body engagement members may beremoved after appropriate positioning to improve comfort and conveniencefor the user.

In some examples, a wearable device may implement a custom-fit bodyengagement member that engages with an anatomical feature of the user.The custom-fit body engagement member may be produced in any suitableway, such as by a mill, a lathe, a 3D printer, injection molding, or anyother suitable means of rapid prototyping or low-volume manufacture. Thecustom-fit configuration may be obtained in any suitable way, such asthrough direct or indirect 3D scanning, impression molding,photogrammetry, sample fitting, hand measurement, or combinationthereof, of the user.

In some examples, a wearable device may be configured for consistentplacement on the user’s body based on a custom fit design. For instance,a 3D scan of the exterior topology of the region-of-interest on theuser’s body may be used to create a custom support assembly. The customsupport assembly may be used in conjunction with a custom designed andfabricated wearable device (e.g., helmet). Alternatively, the customsupport assembly may be configured to be used with (e.g., connected toor supported by) an off-the- shelf wearable device (e.g., helmet orother wearable component fabricated in predetermined shapes and/orsizes), thereby allowing a customized fit for the user without requiringa costly fully custom fabricated unit. The custom support assembly maybe a separate piece permanently affixed to a wearable device.Alternatively, the custom support assembly may be removable orcompletely integrated into the wearable device during fabrication.

In some examples, the custom support assembly may be optimized through acomputerized-algorithm to minimize or increase pressure on the user’sbody in specific areas by changing a modifiable parameter of the supportassembly (e.g., the density, shape, material, spacing, or any otherparameter of the support assembly). Additionally or alternatively, thecustom support assembly may be optimized for thermal safety and/orcomfort, such as increasing airflow or insulation in specific areas.

A 3D scan of the exterior topology of the region-of-interest on theuser’s body may be obtained in any suitable way. In some examples, oneor more kiosks may be provided at point-of-sale locations where usersmay be scanned by a 3D scanner and receive a 3D print of their customsupport assembly. The custom support assembly may also be installed intoone of the previously mentioned semi-custom wearable devices (e.g.,helmets) while the users wait. Such methods may provide time- andcost-effective means of providing a custom fit wearable device withtargeted placement of a wearable assembly or wearable module. Inaddition, such methods provide significant performance benefits byoptimizing the position of wearable assemblies and wearable modules,resulting in an improved experience for the user at a lower overallall-in cost. Additionally, cosmetic and/or aesthetic modifications to awearable device and/or support assembly design may be incorporated toallow further customization of the wearable device and opticalmeasurement system to suit user tastes and preferences.

Additionally or alternatively to mechanical systems and methods, asposition alignment system 1306 may implement sensor-based devices andalignment methods. Sensor-based systems and methods involve the use of asensor (e.g., a camera, a time-of-flight sensor, etc.) to determine thecorrect positioning of wearable device 1304 on the user’s body. As willbe described below in more detail, the sensor may be integrated intowearable device 1304, included in another device worn by the user, orincluded in a separate device that is not worn by the user. The sensormay be used for an initial fitting and not needed to be performed forsubsequent uses, or it may be used for active fitting over time by beingimplemented for each system use or over a defined or variable usageroutine. Cameras may be monoscopic or stereoscopic and may determine theposition of the wearable device based on image feature recognition,depth sensing (e.g., time-of-flight), photogrammetric processing, etc.The cameras may image in visible light and/or non-visible light (e.g.,infrared).

In an integrated position alignment system, one or more sensors may beintegrated with (e.g., included in, supported by, etc.) wearable device1304 and used to determine a position of wearable device 1304, as shownin FIG. 15 . FIG. 15 shows an exemplary wearable device 1500 (e.g.,wearable device 1304) including a support assembly 1502, a plurality ofwearable module assemblies 1504 (e.g., wearable assemblies 1308), and anintegrated sensor 1506 supported by support assembly 1502 (e.g., by abody support portion). Integrated sensor 1506 may be communicativelycoupled with a processing unit (not shown) configured to receive andprocess a detection result of integrated sensor 1506. Integrated sensor1506 and/or the processing unit may implement position alignment system1306. The processing unit may be included in wearable device 1500 (e.g.,may be supported by support assembly 1502 or included in a wearablemodule included in a wearable module assembly 1504) or located remotelyfrom wearable device 1500 (e.g., in a remote controller unit).

In some examples, integrated sensor 1506 comprises a camera registeredwith wearable device 1500 (e.g., registered with support assembly 1502and/or one or more wearable module assemblies 1504) and configured toimage the front of the user’s head 1508, as indicated by dashedfield-of-view lines 1510. Additionally or alternatively, one or morecameras may be supported by support assembly 1502 above the user’s earsand configured to image the user’s ears. The camera(s) may beimplemented by any suitable imaging device. Position alignment system1306 may identify, based on the captured image(s) depicting the user’sbody, anatomical features (e.g., the tip of the nose, ears, moles on theuser’s skin, eyebrows, eyes, the chin, cheekbones, lips, scars, etc.)and record in memory the reference positions, in the captured image(s),of the anatomical features. The next time the user wears the wearabledevice 1500, position alignment system 1306 may compare the image(s)captured by the cameras with the previously recorded reference positionsto determine if the current position of wearable device 1500 isconsistent with the prior recorded reference position.

In additional or alternative examples, integrated sensors 1506 may beconfigured to determine a distance to a particular anatomical feature.For example, integrated sensor 1506 may be implemented by atime-of-flight sensor, a line scan ranging system, or any other suitabledepth sensor configured to measure a distance to the user’s nose (orother anatomical feature). Position alignment system 1306 may record themeasured distance to the particular anatomical feature. The next timethe user wears wearable device 1500, position alignment system 1306 maycompare a currently measured distance by the same integrated sensor 1506with the previously recorded reference measurement to determine if theposition of wearable device 1500 is consistent with the prior recordedreference position.

In some examples, one or more integrated sensors 1506 may be configuredto generate data representative of a 3D depth map of the user’s body(e.g., the user’s face, the user’s head, etc.). The 3D depth map may beused in any of the ways described above to determine the position ofwearable device 1500 relative to head 1508.

In the examples described above, integrated sensor 1506 is configured todetermine the position of wearable device 1500 relative to an anatomicalfeature. In additional or alternative examples, integrated sensor 1506may be configured to determine the position of wearable device 1500relative to a non-anatomical feature (not shown), such as anotherwearable unit (e.g., eyeglasses, a virtual reality (VR) or augmentedreality (AR) headset, a hearing aid, an earring, a nose ring, a tattoo,etc.). For example, integrated sensor 1506 may be configured to image(or measure a distance to) a VR/AR headset worn by the user. In someexamples, a fiducial marker may be placed on the non-anatomical featureto act as a specific reference point.

In some examples, wearable device 1500 may be configured to determine aposition of wearable device 1500 on user’s head 1508 based on anotherwearable device (e.g., a VR/AR headset) that has been registered withthe user’s head 1508. For example, a VR/AR headset may be registered tothe user’s head, such as by eye alignment (e.g., eye tracking),photogrammetry, or any other suitable alignment method. A position ofwearable device 1500 may then be determined relative to the VR/ARheadset and, hence, relative to head 1508. In some examples, wearabledevice 1500 may include one or more connection members configured tophysically connect wearable device 1500 with the VR/AR headset. In thisway, the VR/AR headset may be used to positionally align wearable device1500 with head 1508.

Additionally or alternatively to integrated sensors, position alignmentsystem 1306 (see FIGS. 13A and 13B) may use one or more external sensorsthat are external to (e.g., physically independent of or separated from)wearable device 1304, as shown in FIG. 16 . FIG. 16 is similar to FIG.15 except that in FIG. 16 integrated sensor 1506 is replaced withexternal sensor 1602. Any of the methods described above that may beperformed with integrated sensor 1506 may also be performed withexternal sensor 1602. For example, external sensor 1602 may beconfigured to capture one or more images of the user and wearable device1500, generate a depth map of the user and wearable device 1500, and/ormeasure a distance to the user or wearable device 1500. To illustrate,external sensor 1602 may comprise a camera configured to capture imagesdepicting the user and wearable device 1500 (including support assembly1502) on head 1508. Position alignment system 1306 may identify, basedon the captured image(s), wearable device 1500 and one or moreanatomical features (e.g., the nose). Position alignment system 1306 maythen record in memory the position of wearable device 1500 relative tothe one or more anatomical features. The next time the user wears thewearable device 1500, position alignment system 1306 may compareimage(s) captured by the camera with the previously recorded referenceimages to determine if the position of wearable device 1500 isconsistent with the prior recorded position.

In some examples, position alignment system 1306 may use one or morereference points (e.g., fiducial markers) on wearable device 1500 (e.g.,on support assembly 1502, on a wearable assembly, or on a wearablemodule included in wearable device 1500) and/or one or more anatomicalfeatures (e.g., eyes, ears, nose, scars, moles, etc.) or non-anatomicalfeatures (e.g., eyeglasses, earrings, nose rings, etc.) to determine aposition of the reference point on wearable device 1500 relative to theanatomical or non-anatomical feature. In some embodiments, a fiducialmarker may be placed on the user’s body (e.g., head or face) independentof wearable device 1500 or any other wearable device or unit (e.g.,VR/AR glasses, eyeglasses, etc.) worn by the user. The fiducial markermay be, for example, a retroreflective marker, such as a marker used for3D imaging of bodies and/or for tracking movements to generate animatedimages. Such fiducial marker may be attached to a known mark on theuser’s body (e.g., shoulders, nose, ears, etc.) and one or moreadditional fiducial markers could be attached to wearable device 1500.In this way, the position of wearable device 1500 relative to thefiducial marker on the user’s body can be determined and adjusted toachieve the proper positioning.

In some examples, external sensor 1602 and a processing unit may beincluded as part of optical measurement system 1302. For example,external sensor 1602 and the processing unit may be included in a remotecontroller (e.g., controller 112) or computing device (e.g., laptop,processing unit, remote processor 512, etc.). In alternative examples,external sensor 1602 and/or the processing unit may be included in amobile device (e.g., a smartphone, a tablet, etc.).

Additionally or alternatively to mechanical- and sensor-based positionalignment systems and methods, position alignment system 1306 may usesignal-based position alignment systems and methods in which positionalignment is based on signals detected by wearable assemblies 1308included in wearable device 1304. For example, the user may be promptedto perform a routine task for which the neural signal is known. Opticalmeasurement system 1302 may measure the neural signals duringperformance of the task. Position alignment system 1306 may determine,based on the location (e.g., particular detectors or wearable modules inwearable device 1304) of the detected neural signal that matches theknown signal, the position of wearable device 1304 relative to theuser’s head. In additional or alternative examples, a stimulus for whichthe evoked neural or biological response signal is known may be appliedto the user to determine and guide adjustment of the position ofwearable device 1304 on the user.

In the examples described above, position alignment system 1306 maydetermine a position of wearable device 1304 and determine if a currentposition of wearable device 1304 matches a recorded reference positionfor wearable device 1304. In some examples, position alignment system1306 may also be configured to notify (e.g., via a visual, audio, and/orhaptic notification) the user when the present position of wearabledevice 1304 is the same as a previously recorded reference position ofwearable device 1304 on the body of the user. Additionally oralternatively, position alignment system 1306 may guide the user toadjust wearable device 1304 to the recorded reference position. Forinstance, position alignment system 1306 may show presently capturedimages from integrated sensor 1506 and/or external sensor 1602 and thereference position on a display screen of a connected device (e.g., acomputer, a smartphone, a tablet, a remote controller, etc.) so the usercan easily determine how to adjust wearable device 1304. Positionalignment system 1306 may be configured to guide the user to repositionwearable device 1304 until the present position substantially matchesthe recorded reference position.

Wearable device 1304 may be adjusted in any of the ways describedherein. For example, wearable device 1304 may be adjusted manually.Additionally or alternatively, position alignment system 1306 mayautomatically adjust wearable device 1304 by driving, based on thepresent position and the reference position, one or more mechanicalactuators or motors to adjust a position of wearable device 1304 (e.g.,a position of body support portion 804, a position of support members806, and/or a position of a wearable assembly, wearable module assembly,and/or wearable module supported by support members 806). In someembodiments, position alignment system 1306 may enable consistentpositioning of wearable device 1304 during multiple different usesessions with no more than one (1) centimeter (cm) of variability.

In the embodiments described above, position alignment system 1306 maydetermine the position of wearable device 1304 as a whole relative tothe user’s body (e.g., the user’s head). Additionally or alternatively,position alignment system 1306 may determine the position of eachindividual wearable assembly, wearable module assembly, and/or wearablemodule relative to the user’s body in any of the ways described abovefor positioning of wearable device 1304. In some examples, positionalignment system 1306 may determine that only one wearable assembly 1308(e.g., wearable module assembly 1006-2, see FIG. 10 ) in wearable device1304 is out of alignment and thus guide the user to reposition thatwearable assembly 1308.

Position alignment system 1306 may also be used to perform coarseadjustments prior to use of wearable device 1304 by the user. Forinstance, measurements (size, location, etc.) of the user’s body (e.g.,head) may be input as fitting data to position alignment system 1306.Position alignment system 1306 may model, based on the fitting data, theshape of the user’s body and determine the appropriate size and positionsettings for the wearable device, support assembly (e.g., body supportportion and support members), and wearable assemblies. In this way, thewearable device can be coarsely adjusted prior to use by the user tospeed up the positioning procedure.

In some examples, a 3D model of the target (e.g., user’s brain), such asan MRI scan, a CT scan, an EEG scan, a transcranial doppler ultrasoundscan, a conventional ultrasound scan, and the like, may be input asmodel data to position alignment system 1306. Position alignment system1306 may use the model data to identify the locations of the target andspecific regions-of-interest and identify proper positions of wearabledevice 1304 (e.g., a position of wearable device 1304 on the user’sbody, a position of support members in wearable device 1304, and/or aposition of one or more wearable assemblies 1308 supported by thesupport members) to image the target at the region-of-interest.

The preceding description describes using various wearable devicepositioning systems and method to aid adjustment of the position of awearable device, wearable assemblies, wearable module assemblies, and/orwearable modules on the user’s body. In other embodiments, it may bepossible to use wearable device position information to calibrate thewearable module detection results without requiring the user toreposition the wearable device. By knowing the position of the wearabledevice relative to the user’s body, an optical measurement system orposition alignment system can correct the acquired data to correspond todata acquired from a recorded reference position. For example, wearablemodules 1008 (see FIGS. 10 and 11 ) may be calibrated to identify wherethey are relative to each other. This may be done in any suitable way,such as is described in the co-pending Provisional Pat. Application No.63/071,473, filed on Aug. 28, 2020, entitled “Estimation ofSource-detector Separation in an Optical Measurement System,”incorporated herein in its entirety. In such system, the observation ofa plurality of known neural signal sources (e.g., three) having knownpositions relative to one other and to the entire signal area ofinterest may be used to infer the position to the surrounding morphology(particularly if the detected neural signals are consistent enough overtime, e.g., have no neural plasticity or the like which would alter theresponse to a known calibration stimulus).

In some examples, optical measurement systems described herein (e.g.,optical measurement system 100 or optical measurement system 1302) mayinclude a processing unit configured to perform one or more operationsbased on photon arrival times detected by the detectors describedherein, and perform one or more position alignment operations. Forexample, FIGS. 17A-17B show illustrative configurations 1700-1 and1700-2 of an exemplary optical measurement system 1702 in accordancewith the principles described herein.

Optical measurement system 1702 may be an implementation of opticalmeasurement system 100 or optical measurement system 1302 and, as shown,includes a wearable device 1704 and a processing unit 1706. Wearabledevice 1704 may be implemented by any wearable device described hereinand may include a wearable assembly 1708. Processing unit 1706 mayperform any operations described herein. In some examples, processingunit 1706 implements position alignment system 1306. Wearable assembly1708 may be implemented by any wearable assembly described herein. Insome examples, optical measurement system 1702 may include a pluralityof wearable assemblies 1708. Optical measurement system 1702 may alsoinclude any other components as may serve a particular implementation.

In configuration 1700-1, processing unit 1706 is included in wearabledevice 1704 (e.g., supported by support assembly 802, included wearableassembly 1708, included in a housing of a wearable module 702, etc.). Inconfiguration 1700-2, processing unit 1706 is not included in wearabledevice 1704 (i.e., processing unit 1706 is housed in an additionalhousing of a device located external to wearable device 1704). Eitherconfiguration 1700-1 or 1700-2 may be used in accordance with thesystems, circuits, and methods described herein.

Detectors on wearable assembly 1708 may output signals representative ofphoton arrivals, as described herein. Processing unit 1706 is configuredto receive the output signals and perform one or more operations basedon the signals. For example, processing unit 1706 may generatemeasurement data (e.g., one or more histograms) based on the signals, asdescribed herein.

As mentioned, in configuration 1700-2, processing unit 1706 is notincluded in wearable device 1704. For example, processing unit 1706 maybe included in a wearable device separate from wearable device 1704. Toillustrate, processing unit 1706 may be included in a wearable deviceconfigured to be worn off the head (e.g., on a belt) while wearabledevice 1704 is worn on the head. In these examples, one or morecommunication interfaces (e.g., cables, wireless interfaces, etc.) maybe used to facilitate communication between wearable device 1704 and theseparate wearable device.

Additionally or alternatively, in configuration 1700-2, processing unit1706 may be remote from the user (i.e., not worn by the user). Forexample, processing unit 1706 may be implemented by a stand-alonecomputing device communicatively coupled to wearable device 1704 by wayof one or more communication interfaces (e.g., cables, wirelessinterfaces, etc.).

In some examples, processing unit 1706 may be distributed betweenmultiple devices and/or multiple locations as may serve a particularimplementation. Processing unit 1706 may be implemented by processor108, controller 112, control circuit 244, and/or any other suitableprocessing and/or computing device or circuit.

For example, FIG. 18 illustrates an exemplary implementation ofprocessing unit 1706 in which processing unit 1706 includes a memory(storage facility) 1802 and a processor (processing facility) 1804configured to be selectively and communicatively coupled to one another.In some examples, memory 1802 and processor 1804 may be distributedbetween multiple devices and/or multiple locations as may serve aparticular implementation.

Memory 1802 may be implemented by any suitable non-transitorycomputer-readable medium and/or non-transitory processor-readablemedium, such as any combination of non-volatile storage media and/orvolatile storage media. Exemplary non-volatile storage media include,but are not limited to, read-only memory, flash memory, a solid-statedrive, a magnetic storage device (e.g., a hard drive), ferroelectricrandom-access memory (“RAM”), and an optical disc. Exemplary volatilestorage media include, but are not limited to, RAM (e.g., dynamic RAM).

Memory 1802 may maintain (e.g., store) executable data used by processor1804 to perform one or more of the operations described herein. Forexample, memory 1802 may store instructions 1806 that may be executed byprocessor 1804 to perform any of the operations described herein.Instructions 1806 may be implemented by any suitable application,program (e.g., sound processing program), software, code, and/or otherexecutable data instance. Memory 1802 may also maintain any datareceived, generated, managed, used, and/or transmitted by processor1804.

Processor 1804 may be configured to perform (e.g., execute instructions1806 stored in memory 1802 to perform) various operations describedherein. For example, processor 1804 may be configured to perform any ofthe operations described herein as being performed by processing unit1706.

FIGS. 19-24 illustrate embodiments of a wearable device 1900 thatincludes elements of the optical measurement systems and/or wearableassemblies described herein. In particular, the wearable devices 1900include a plurality of modules 1902, similar to modules 702 describedherein. For example, each module 1902 includes a light source 704 and aplurality of detectors 706. Light source 704 may be implemented by or besimilar to one or more light sources described herein (e.g., lightsource 110). Each detector 706 may implement or be similar to one ormore detectors or detector assemblies described herein (e.g., detector104) and may include a plurality of photodetectors. The wearable devices1900 may each also include a controller (e.g., controller 112) and aprocessor (e.g., processor 108) and/or be communicatively connected to acontroller and/or a processor. In general, wearable device 1900 may beimplemented by any suitable headgear and/or clothing article configuredto be worn by a user. The headgear and/or clothing article may includebatteries, cables, and/or other peripherals for the components of theoptical measurement systems described herein. In some examples, theheadgear includes one or more modules 1902. Additionally oralternatively, modules 1902 are included in or implemented by modules702.

FIG. 19 illustrates an embodiment of a wearable device 1900 in the formof a helmet with a handle 1904. A cable 1906 extends from the wearabledevice 1900 for attachment to a battery or hub (with components such asa processor or the like). FIG. 20 illustrates another embodiment of awearable device 1900 in the form of a helmet showing a back view. FIG.21 illustrates a third embodiment of a wearable device 1900 in the formof a helmet with the cable 1906 leading to a wearable garment 1908 (suchas a vest or partial vest) that can include a battery or a hub (e.g.,processing unit 1706). Alternatively or additionally, the wearabledevice 1900 can include a crest 1910 or other protrusion for placementof the hub or battery.

FIG. 22 illustrates another embodiment of a wearable device 1900 in theform of a cap with a wearable garment 1908 in the form of a scarf thatmay contain or conceal a cable, battery, and/or hub. FIG. 23 illustratesadditional embodiments of a wearable device 1900 in the form of a helmetwith a one-piece scarf 1908 or two-piece scarf 1908-1. FIG. 24illustrates an embodiment of a wearable device 1900 that includes a hood1910 and a beanie 1912 which contains the modules 1902, as well as awearable garment 1908 that may contain a battery or hub.

In some examples, a wearable device (e.g., wearable device 800 or 1900)may include a pressing member configured to press, to a conformablefitting position as may serve a particular use session, the plurality ofwearable modules toward the surface of the body of the user when thewearable module assembly is worn on the body of the user. Thus, thepressing member may help maintain contact of the light sources (e.g.,light sources 704) and detectors (e.g., detector 706) with the bodysurface. The pressing member may include, for example, an elastic band,a strap, a hat, an inflatable bag within a helmet, or any other suitabledevice configured to press the wearable assembly against the bodysurface. For instance, the helmets shown in FIGS. 19 and 20 may coverwearable module assembly 700 and be configured to press modules 702against the user’s head. In some examples, the fit of the helmets isadjustable to produce the pressing force, as may be required, in orderto support the helmet on the desired region-of-interest on the user’shead. Alternatively, the helmets may include an inflatable airbag thatpresses wearable module assembly 700 against the user’s head.

FIG. 25 illustrates an exemplary method 2500. While FIG. 25 illustratesexemplary operations according to one embodiment, other embodiments mayomit, add to, reorder, and/or modify any of the operations shown in FIG.25 . One or more of the operations shown in FIG. 25 may be performed byoptical measurement system 100, 1302, or 1702, or position alignmentsystem 1306, or any components included therein, and/or anyimplementation thereof.

In operation 2502, a present position, on a body of a user, of awearable assembly being worn on the body of the user is determined.Operation 2502 may be performed in any of the ways described herein.

In operation 2504, it is determined whether the present position of thewearable assembly is the same (within a predetermined tolerance, e.g., 1cm) as a previously used reference position of the wearable assembly onthe body of the user. Operation 2504 may be performed in any of the waysdescribed herein.

Operations 2502 and 2504 may be repeated, as needed, until it isdetermined that the present position of the wearable assembly is thesame as the previously used reference position of the wearable assemblyon the body of the user. For example, if the present position isdetermined to not be the same as the previously used reference position,the method returns to operation 2502. If the present position isdetermined to be the same as the previously used reference position, themethod proceeds to operation 2506.

In operation 2506, a notification is provided in response to adetermination that the present position of the wearable assembly is thesame as the previously used reference position of the wearable assembly.The notification may indicate that the present position of the wearableassembly is the same as the previously used reference position of thewearable assembly. Operation 2506 may be performed in any of the waysdescribed herein.

In some examples, a non-transitory computer-readable medium storingcomputer-readable instructions may be provided in accordance with theprinciples described herein. The instructions, when executed by aprocessor of a computing device, may direct the processor and/orcomputing device to perform one or more operations, including one ormore of the operations described herein. Such instructions may be storedand/or transmitted using any of a variety of known computer-readablemedia.

A non-transitory computer-readable medium as referred to herein mayinclude any non-transitory storage medium that participates in providingdata (e.g., instructions) that may be read and/or executed by acomputing device (e.g., by a processor of a computing device). Forexample, a non-transitory computer-readable medium may include, but isnot limited to, any combination of non-volatile storage media and/orvolatile storage media. Exemplary non-volatile storage media include,but are not limited to, read-only memory, flash memory, a solid-statedrive, a magnetic storage device (e.g. a hard disk, a floppy disk,magnetic tape, etc.), ferroelectric random-access memory (“RAM”), and anoptical disc (e.g., a compact disc, a digital video disc, a Blu-raydisc, etc.). Exemplary volatile storage media include, but are notlimited to, RAM (e.g., dynamic RAM).

FIG. 26 illustrates an exemplary computing device 2600 that may bespecifically configured to perform one or more of the processesdescribed herein. Any of the systems, units, computing devices, and/orother components described herein may be implemented by computing device2600.

As shown in FIG. 26 , computing device 2600 may include a communicationinterface 2602, a processor 2604, a storage device 2606, and aninput/output (“I/O”) module 2608 communicatively connected one toanother via a communication infrastructure 2610. While an exemplarycomputing device 2600 is shown in FIG. 26 , the components illustratedin FIG. 26 are not intended to be limiting. Additional or alternativecomponents may be used in other embodiments. Components of computingdevice 2600 shown in FIG. 26 will now be described in additional detail.

Communication interface 2602 may be configured to communicate with oneor more computing devices. Examples of communication interface 2602include, without limitation, a wired network interface (such as anetwork interface card), a wireless network interface (such as awireless network interface card), a modem, an audio/video connection,and any other suitable interface.

Processor 2604 generally represents any type or form of processing unitcapable of processing data and/or interpreting, executing, and/ordirecting execution of one or more of the instructions, processes,and/or operations described herein. Processor 2604 may performoperations by executing computer-executable instructions 2612 (e.g., anapplication, software, code, and/or other executable data instance)stored in storage device 2606.

Storage device 2606 may include one or more data storage media, devices,or configurations and may employ any type, form, and combination of datastorage media and/or device. For example, storage device 2606 mayinclude, but is not limited to, any combination of the non-volatilemedia and/or volatile media described herein. Electronic data, includingdata described herein, may be temporarily and/or permanently stored instorage device 2606. For example, data representative ofcomputer-executable instructions 2612 configured to direct processor2604 to perform any of the operations described herein may be storedwithin storage device 2606. In some examples, data may be arranged inone or more databases residing within storage device 2606.

I/O module 2608 may include one or more I/O modules configured toreceive user input and provide user output. I/O module 2608 may includeany hardware, firmware, software, or combination thereof supportive ofinput and output capabilities. For example, I/O module 2608 may includehardware and/or software for capturing user input, including, but notlimited to, a keyboard or keypad, a touchscreen component (e.g.,touchscreen display), a receiver (e.g., an RF or infrared receiver),motion sensors, and/or one or more input buttons.

I/O module 2608 may include one or more devices for presenting output toa user, including, but not limited to, a graphics engine, a display(e.g., a display screen), one or more output drivers (e.g., displaydrivers), one or more audio speakers, and one or more audio drivers. Incertain embodiments, I/O module 2608 is configured to provide graphicaldata to a display for presentation to a user. The graphical data may berepresentative of one or more graphical user interfaces and/or any othergraphical content as may serve a particular implementation.

In the preceding description, various exemplary embodiments have beendescribed with reference to the accompanying drawings. It will, however,be evident that various modifications and changes may be made thereto,and additional embodiments may be implemented, without departing fromthe scope of the invention as set forth in the claims that follow. Forexample, certain features of one embodiment described herein may becombined with or substituted for features of another embodimentdescribed herein. The description and drawings are accordingly to beregarded in an illustrative rather than a restrictive sense.

What is claimed is:
 1. An optical measurement system comprising: awearable device configured to be worn on a body of a user, comprising: asupport assembly; and a wearable assembly supported by the supportassembly and comprising: a plurality of light sources configured to emita plurality of light pulses toward a target within the body of the user;and a plurality of detectors each configured to receive a set of photonsincluded in a light pulse included in the plurality of light pulsesafter the set of photons is scattered by the target; and a positionalignment system configured to facilitate positioning of the wearableassembly at a same position on the body of the user during different usesessions of the wearable device.
 2. The optical measurement system ofclaim 1, wherein the position alignment system comprises a bodyengagement member supported by the support assembly and configured toengage with an anatomical feature on the body of the user.
 3. Theoptical measurement system of claim 1, wherein: the position alignmentsystem comprises an imaging device configured to capture an image of thebody of the user; and the position alignment system is configured todetermine, based on the image of the body of the user, a presentposition of the wearable assembly on the body of the user.
 4. Theoptical measurement system of claim 3, wherein the imaging device isincluded in the wearable device.
 5. The optical measurement system ofclaim 3, wherein the imaging device is separate from the wearable deviceand the image of the body the user depicts the support assembly worn onthe body of the user.
 6. The optical measurement system of claim 1,wherein the position alignment system is configured to: acquire, from anadditional wearable device worn by the user, information indicating aposition of the additional wearable device on the body of the user; anddetermine, based on the position of the additional wearable device onthe body of the user, a present position of the wearable assembly on thebody of the user.
 7. The optical measurement system of claim 1, whereinthe position alignment system is configured to determine, based on depthdata representative of a depth map of the body of the user and thesupport assembly worn on the body of the user, a present position of thewearable assembly on the body of the user.
 8. The optical measurementsystem of claim 1, wherein the position alignment system is configuredto determine, based on a detection result of the plurality of detectorswhile the support assembly is worn on the body of the user, a presentposition of the wearable assembly on the body of the user.
 9. Theoptical measurement system of claim 1, wherein: the different usesessions comprise a first use session and a second use session that isseparate from and subsequent to the first use session; and the positionalignment system is further configured guide, during the second usesession, the user to adjust the position of the wearable assembly sothat the wearable assembly is located at the same position on the bodyof the user during the second use session as during the first usesession.
 10. The optical measurement system of claim 1, wherein: theposition of the wearable assembly on the support assembly is adjustable;and the wearable assembly is configured to be positioned at the sameposition on the body of the user by adjusting the position of thewearable assembly on the support assembly.
 11. The optical measurementsystem of claim 1, wherein: the support assembly comprises a supportmember; the wearable assembly is supported by the support member; andone or more of a position, a length, or a tension of the support memberis adjustable.
 12. The optical measurement system of claim 1, furthercomprising an additional wearable assembly supported by the supportassembly, wherein the support assembly comprises an adjustable connectorthat connects the wearable assembly with the additional wearableassembly.
 13. The optical measurement system of claim 1, wherein: thesupport assembly comprises a plurality of support members; and a tensionof the plurality of support members is adjustable.
 14. The opticalmeasurement system of claim 1, wherein the support assembly includes alocking member configured to lock the wearable assembly at the positionon the support assembly.
 15. A method comprising: determining, by aposition alignment system, a present position, on a body of a user, of awearable assembly being worn on the body of the user, the wearableassembly comprising: a plurality of light sources configured to emit aplurality of light pulses toward a target within the body of the user;and a plurality of detectors each configured to receive a set of photonsincluded in a light pulse included in the plurality of light pulsesafter the set of photons is scattered by the target; and providing, bythe position alignment system, a notification indicating that thepresent position of the wearable assembly is the same as a previouslyused reference position of the wearable assembly on the body of theuser.
 16. The method of claim 15, further comprising: guiding, by theposition alignment system, the user to adjust the position of thewearable assembly so that the present position of the wearable assemblyis the same as the previously used reference position of the wearableassembly on the body of the user.
 17. The method of claim 15, whereinthe determining of the present position of the wearable assembly on thebody of the user comprises: acquiring, by the position alignment system,image data representative of an image of the body of the user capturedby an imaging device; identifying, by the position alignment systembased on the image data, an anatomical feature on the body of the userand depicted in the image of the body of the user; and determining, bythe position alignment system based on the image data, the position ofthe wearable assembly on the body of the user relative to the anatomicalfeature on the body of the user.
 18. The method of claim 17, wherein theimaging device is registered with the wearable assembly.
 19. The methodof claim 15, wherein the determining of the present position of thewearable assembly on the body of the user is based on a depth map of thebody of the user and the wearable assembly.
 20. The method of claim 15,wherein the determining of the present position of the wearable assemblyon the body of the user comprises: acquiring, by the position alignmentsystem based on a detection result of the plurality of detectors, aneural signal based on performance of a task by the user; comparing, bythe position alignment system, the acquired neural signal with a knownneural signal for performance of the task; and determining, by theposition alignment system based on the comparing of the acquired neuralsignal with the known neural signal, the present position of thewearable assembly on the body of the user.